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ANATOMY OF NECK
GENERAL PREVIEW OF NECK
• The neck is the part of the body, on many terrestrial or secondarily aquatic vertebrates, that distinguishes the head from the torso or trunk. The Latin term signifying "of the neck" is cervical
• The neck supports the weight of the head and protects the nerves that carry sensory and motor information from the brain down to the rest of the body. In addition, the neck is highly flexible and allows the head to turn and flex in all directions.
NECK
BOUNDARY SUPERIOR• pericraniocervical lineINFERIOR• manubrium sterni• clavicle• spine of scapula
Pericraniocervical line
• Separate between the head and neck• Anterior - Symphysis menti• Posterior - Inion• Inferior border and angle of mandible, mastoid process,• superior nuchal line,• external occipital• protuberance
UNDERLYING STRUCTURES OF HEAD AND NECK
• Skin• Muscles• Glandular tissue• Blood vessels• Lymphatics• Fascial space
SURFACE ANATOMY
• A branch of gross anatomy that examines shapes and markings on the surface of the body as they relate to deeper structures.• Essential in locating and identifying anatomic structures prior to studying internal gross anatomy.• Health-care personnel use surface anatomy to help diagnose medical conditions and to treat patients.
SURFACE ANATOMY OF NECK
• In the middle line below the chin can be felt the body of the hyoid bone.
• Just below which is the prominence of the thyroid cartilage called "Adam's apple, better marked in men than in women.
• Still lower the cricoid cartilage is easily felt, while between this and the suprasternal notch the trachea and isthmus of the thyroid gland may be made out.
• At the side the outline of the sternomastoid muscle is the most striking mark; it divides the anterior triangle of the neck from the posterior.
• The upper part of the former contains the submaxillary gland also known as the submandibular glands which lies just below the posterior half of the body of the jaw.
• The Adam's apple clinically known as the laryngeal prominence is a lump/ protrusion formed by the angle of the thyroid cartilage surrounding the larynx. This is an often used centering point in radiography for the cervical spine AP view.
• The thyroid is one of the largest endocrine glands in the body. This gland is found in the anterior neck inferior to the mandible. The thyroid controls metabolism in the body and is one of the most sensitive areas of the body to radiation.
• The line of the common and the external carotid arteries may be marked by joining the sterno-clavicular articulation to the angle of the jaw.
• The eleventh or spinal accessory nerve corresponds to a line drawn from a point midway between the angle of the jaw and the mastoid process to the middle of the posterior border of the sterno-mastoid muscle and thence across the posterior triangle to the deep surface of the trapezius.
• The external jugular vein can usually be seen through the skin; it runs in a line drawn from the angle of the jaw to the middle of the clavicle, and close to it are some small lymphatic glands.
• The anterior jugular vein is smaller, and runs down about half an inch from the middle line of the neck.
• The clavicle or collar-bone forms the lower limit of the neck, and laterally the outward slope of the neck to the shoulder is caused by the trapezius muscle.
• Lymph nodes are components of the lymphatic system and there are approximately 300 lymph nodes in the neck.
• Nodes act as filters, with an internal honeycomb of reticular connective tissue filled with lymphocytes that collect and destroy bacteria and viruses.
• When the body is fighting an infection, lymphocytes multiply rapidly and produce a characteristic swelling of the lymph nodes.
• The location of the Preauricular, Submandibular, Submental, Anterior Cervical and Supraclavicular superficial node chains are shown .
• In the neck, the Platysma when contracted throws the skin into oblique ridges parallel with the fasciculi of the muscle.
• The Sternocleidomastoid has the most important influence on the surface form of the neck . When the muscle is at rest its anterior border forms an oblique rounded edge ending below in the sharp outline of the sternal head, the posterior border is only distinct for about 2 or 3 cm above the middle of the clavicle.
• The sternal heads of the two muscles are separated by a V- shaped depression, in which are the Sternohyoid and Sternothyroid.
• Above the hyoid bone, near the middle line, the anterior belly of the Digastric produces a slight convexity.
• The anterior border of the Trapezius presents as a faint ridge running from the superior nuchal line, downward and forward to the junction of the intermediate and lateral thirds of the clavicle.
• Between the Sternocleidomastoideus and the Trapezius is the posterior triangle of the neck, the lower part of which appears as a shallow concavity—the supraclavicular fossa.
• In this fossa, the inferior belly of the Omohyoid, when in action, presents as a rounded cord-like elevation a little above, and almost parallel to, the clavical
• ARTERIES.—The positions of several of the larger arteries can be ascertained from their pulsations. 8 The subclavian artery can be felt by making pressure downward, backward, and medialward behind the clavicular head of the Sternocleidomastoideus its transverse cervical branch may be detected parallel to, and about a finger’s breadth above, the clavicle. The common and external carotid arteries can be recognized immediately beneath the anterior edge of the Sternocleidomastoideus. The external maxillary artery can be traced over the border of the mandible just in front of the anterior border of the Masseter, then about 1 cm. lateral to the angle of the mouth, and finally as it runs up the side of the nose.
• The pulsation of the occipital artery can be distinguished about 3 or 4 cm. lateral to the external occipital protuberance; that of the posterior auricular in the groove between the mastoid process and the auricula.
• The course of the superficial temporal artery can be readily followed across the posterior end of the zygomatic arch to a point about 3 to 5 cm. above this, where it divides into its frontal and parietal branches; the pulsation of the frontal branch is frequently visible on the side of the forehead.
• The supraorbital artery can usually be detected immediately above the supraorbital notch or foramen
Triangles of the Neck
• Neck/cervical region/cervix is a complex region that connects the head to the trunk.
• Spinal cord, nerves, trachea, esophagus, and major vessels traverse this highly flexible area.
• Neck contains other organs and several important glands.
• Neck can be subdivided into anterior, posterior, and lateral regions.
The Anterior Region of the Neck
Has several palpable landmarks, including the larynx, trachea, and sternal notch.The larynx found in the middle of the neck composed of multiple cartilages thyroid cartilage or “Adam’s apple”
• Inferior to the larynx are the cricoid cartilage and trachea.
• Terminates at the sternal (jugular) notch of the manubrium and the left and right clavicles.
The Nuchal Region• The posterior neck region
houses the spinal cord, cervical vertebrae, and associated
structures.• The bump at the lower
boundary of this region is the vertebra prominens.
• Superiorly along the midline of the neck, is the ligamentum nuchae, a thick ligament that runs from C7 to the nuchal lines of the skull.
Left and Right Lateral Portionsof the Neck
• Contain the sternocleidomastoid muscles which partitions the
• neck into two clinically important triangles, an anterior triangle and a posterior triangle.
• Each triangle houses important structures that run through the neck.
• Triangles are further subdivided into smaller triangles.
• Anterior triangle lies anterior to the sternocleidomastoid muscle and inferior to the mandible.
• subdivided into four smaller triangles
Submental, Submandibular Carotid Muscular triangles
The Submental Triangle The most superiorly placed of
the four triangles.• Inferior to the chin in the
midline of the neck.• Partially bounded by the anterior
belly of the digastric muscle.• Contains some cervical lymph
nodes and tiny veins.• With illness these lymph nodes
enlarge and become tender. Palpation can determine
if an infection is present
The Submandibular Triangle
• Inferior to the mandible and lateral to the submental triangle.
• Bounded by the mandible and the bellies of the digastric muscle.
• The submandibular gland is the bulge under the mandible.
The Carotid Triangle
• Bounded by the sternocleidomastoid, omohyoid, and posterior digastric muscles.
• The strong pulsation is the common carotid artery.
• Contains the internal jugular vein and some cervical lymph nodes.
The Muscular Triangle
• Most inferior of the four triangles.
• Contains the sternohyoid and sternothyroid muscles,
as well as the lateral edges of the larynx and the thyroid gland.
• Also contains cervical lymph nodes which are present throughout the neck.
The Posterior Triangle
• Lateral region of the neck.• Posterior to the
sternocleidomastoid muscle.
• Superior to the clavicle inferiorly.
• Anterior to the trapezius muscle.
• Subdivided into two smaller triangles the occipital triangle supraclavicular triangle
The Occipital Triangle
• Larger and more posteriorly placed.
• Bounded by the omohyoid, trapezius, and
• sternocleidomastoid muscles.
• Contains the external jugular vein, the accessory
• nerve, the brachial plexus, and some lymph nodes.
Supraclavicular Triangle• Also called
omoclavicular and subclavian.
• Bounded by the clavicle, omohyoid, and
• sternocleidomastoid muscles.
• Contains part of the subclavian vein and artery as well as some lymph nodes.
CLAVICLE AND STERNUM
• Paired clavicles and the sternal (jugular) notch represent the border between the thorax and the neck.
• On the superior anterior surface where they extend between the base of the neck on the right and left sides laterally to the shoulders. STERNUM : Palpated readily as the midline bony structure in the thorax. The manubrium, the body, and the xiphoid process may also be
palpated.• Sternal angle can be felt as an elevation between the manubrium and
the body.• Sternal angle is clinically important because it is at the level of the
costal cartilage of the second rib. it is often used as a landmark for counting the ribs
ANATOMY OF THE CERVICAL SPINE
Cervical Spine Anatomy
• Primary function• Mobility, support, and
protection of spinal canal and neural structures
Cervical Spine Anatomy• Vertebrae (7)• Intervertebral discs (6) • Pairs of exiting nerve
roots (8)
• Cervical lordosis Occ-C7 averages 40°– Most of the lordosis
occurs at the C1-C2 segment
1
2
3
4
5
6
7
Cervical Spine AnatomyApproximately 50% of flexion-extension motion occurs at occiput-C1Approximately 50% of rotation occurs at C1-C2Lesser amounts of flexion-extension, rotation, and lateral bending occur segmentally between C2-C7
Cervical Spine Anatomy
Cervical Spine Anatomy
• Atypical vertebral • structure C1 (atlas)• Vertebral canal/foramen• Anterior arch • Anterior tubercle• Transverse process• Posterior arch• Transverse foramen • Lateral mass
Occipital condyles
Foramen magnum
Superior
Inferior
Cervical Spine Anatomy• Occiput-C1 segment– The occiput-C1 joints
are synovial joints comprising the convex occipital condyles, which articulate with the concave lateral masses of C1
Cervical Spine Anatomy• Occiput-C1 segment– Motion at the occiput-
C1 segment is restricted primarily to flexion-extension due to bony structures, ligamentous constraints, and the absence of an intervertebral disc
Cervical Spine Anatomy• Atypical cervical • vertebra C2 (axis)• Odontoid process or dens• Vertebral canal/foramen • Facet joints• Transverse process• Transverse foramen • Bifid spinous process• Lamina
anterior view
posterior view
Cervical Spine Anatomy
The odontoid process of the axis (C2) extends cranially to form the axis of rotation with atlas (C1)
Cervical Spine AnatomyC1-C2 segment
The primary motion at the C1-C2 joint is rotation
Cervical Spine Anatomy
• Ligaments– The cervical spine
also features a complex arrangement of ligaments to supplement its structure and mobility
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior longitudinal
ligament– Ligamentum flavum– Intertransverse
ligaments– Interspinous ligaments– Ligamentum nuchae
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior
longitudinal ligament
– Ligamentum flavum– Intertransverse
ligaments– Interspinous
ligaments– Ligamentum nuchae
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior longitudinal
ligament– Ligamentum flavum– Intertransverse
ligaments– Interspinous
ligaments– Ligamentum nuchae
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior longitudinal
ligament– Ligamentum flavum– Intertransverse
ligaments– Interspinous
ligaments– Ligamentum nuchae
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior longitudinal
ligament– Ligamentum flavum– Intertransverse
ligaments– Interspinous
ligaments– Ligamentum nuchae
Cervical Spine Anatomy• Ligaments– Anterior longitudinal
ligament– Posterior longitudinal
ligament– Ligamentum flavum– Intertransverse
ligaments – Interspinous ligaments– Ligamentum nuchae
Cervical Spine Anatomy•Neural elements– 8 pair of cervical nerves– Exit the spinal canal
superior to the vertebrae for which they are numbered• C1 nerves exit the
canal between Occ & C1• C2 nerves exit the
canal between C1 & C2• C8 nerves exit the
canal between C7 , T1
Cervical Spine Anatomy• Arteries– Carotid arteries• Located anterior
and bilateral to the spine
– Vertebral arteries• Enter the
transverse foramen at C6 and continue through C1
Cervical Spine Anatomy• Veins– Jugular veins• Located bilateral
and anterior to the spine.
– Vertebral veins• Located within the
transverse foramen of C1-C7
Cervical Spine Anatomy
Cervical vertebraeGeneral characteristics (C3-C6)
• By convention, the cervical vertebrae are numbered, with the first one (C1) located closest to the skull and higher numbered vertebrae (C2-C7) proceeding away from the skull and down the spine. The general characteristics of the third through sixth cervical vertebrae are described here. The first, second, and seventh vertebrae are extraordinary, and are detailed later.
• The body of these four vertebrae is small, and broader from side to side than from front to back. – The anterior and posterior
surfaces are flattened and of equal depth; the former is placed on a lower level than the latter, and its inferior border is prolonged downward, so as to overlap the upper and forepart of the vertebra below.
– The upper surface is concave transversely, and presents a projecting lip on either side.
• the lower surface is concave from front to back, convex from side to side, and presents laterally shallow concavities which receive the corresponding projecting lips of the underlying vertebra
• The pedicles are directed laterally and backward, and are attached to the body midway between its upper and lower borders, so that the superior vertebral notch is as deep as the inferior, but it is, at the same time, narrower.
• The laminae are narrow, and thinner above than below; the vertebral foramen is large, and of a triangular form.
• The spinous process is short and bifid, the two divisions being often of unequal size
The superior and inferior articular processes of cervical vertebrae have fused on either or both sides to form articular pillars, columns of bone that project laterally from the junction of the pedicle and lamina.The articular facets are flat and of an
oval form: the superior face backward, upward, and slightly medially.the inferior face forward, downward, and slightly laterally
• The transverse processes are each pierced by the foramen transversarium, which, in the upper six vertebrae, gives passage to the vertebral artery and vein, as well as a plexus of sympathetic nerves. Each process consists of an anterior and a posterior part. These two parts are joined, outside the foramen, by a bar of bone that exhibits a deep sulcus on its upper surface for the passage of the corresponding spinal nerve.
The anterior portion is the homologue of the rib in the thoracic region, and is therefore named the costal process or costal element. It arises from the side of the body, is directed laterally in front of the foramen, and ends in a tubercle, the anterior tubercle.
The posterior part, the true transverse process, springs from the vertebral arch behind the foramen, and is directed forward and laterally; it ends in a flattened vertical tubercle, the posterior tubercle
Special cervical vertebrae (C1, C2, and C7)
• C1 or atlas: The Atlas is the topmost vertebra, and – along with C2 – forms the joint connecting the skull and spine. Its chief peculiarity is that it has no body, and this is due to the fact that the body of the atlas has fused with that of the next vertebra.
C2 vertebra
• C2 or axis: It forms the pivot upon which C1 rotates. The most distinctive characteristic of this bone is the strong odontoid process (dens) that rises perpendicularly from the upper surface of the body. The body is deeper in front than behind, and prolonged downward anteriorly so as to overlap the upper and front part of the third vertebra.
C7 VERTEBRA• C7 or vertebra prominens: The
most distinctive characteristic of this vertebra is the existence of a long and prominent spinous process, hence the name vertebra prominens. In some subjects, the seventh cervical vertebra is associated with an abnormal pair of ribs, known as cervical ribs. These ribs are usually small, but may occasionally compress blood vessels (such as the subclavian artery) or nerves in the brachial plexus, causing ischemic muscle pain, numbness, tingling, and weakness in the upper limb.
Development• The atlas ossifies from 3 centers.• The atlas is usually ossified from three
centers.• Of these, one appears in each lateral
mass about the seventh week of fetal life, and extends backward; at birth, these portions of bone are separated from one another behind by a narrow interval filled with cartilage.
• Between the third and fourth years they unite either directly or through the medium of a separate center developed in the cartilage.
• At birth, the anterior arch consists of cartilage; in this a separate center appears about the end of the first year after birth, and joins the lateral masses from the sixth to the eighth year
Hyoid bone
The hyoid bone (lingual bone) (Latin os hyoideum) is a horseshoe-shaped bone situated in the anterior midline of the neck between the chin and the thyroid cartilage. At rest, it lies at the level of the base of the mandible in the front and the third cervical vertebra behind
• Unlike other bones, the hyoid is only distantly articulated to other bones by muscles or ligaments. The hyoid is anchored by muscles from the anterior, posterior, and inferior directions and aids in tongue movement and swallowing. The hyoid bone provides attachment to the muscles of the floor of the mouth and the tongue above, the larynx below, and the epiglottis and pharynx behind.
• Its name is derived from the Greek word hyoides meaning "shaped like the letter upsilon" (υ).
Segments
• The bone consists of a central part, called the body and two pairs of cornua, the greater cornu and the lesser cornu.
• Body of hyoid• Greater cornu(2)• Lesser cornu (2)
Embryology
• The second pharyngeal arch gives rise to the lesser cornu of hyoid and the superior part of body of hyoid. The cartilage of the third pharyngeal arch forms the greater cornu of hyoid and the lower portion of the body of hyoid.
Ossification
• The hyoid is ossified from six centers: two for the body, and one for each cornu. Ossification commences in the greater cornua toward the end of fetal life, in the body shortly afterward, and in the lesser cornua during the first or second year after birth. Until middle age the connection between the body and greater cornu is fibrous.
Muscle attachments
• The following muscles are attached to the hyoid:• Superior• Middle pharyngeal constrictor muscle • Hyoglossus muscle• Digastric muscle• Stylohyoid muscle• Geniohyoid muscle• Mylohyoid muscle• INFERIOR• Thyrohyoid muscle• Omohyoid muscle• Sternohyoid muscle
Deep cervical fascia
• The deep cervical fascia (or fascia colli in older texts) lies under cover of the Platysma, and invests the neck; it also forms sheaths for the carotid vessels, and for the structures situated in front of the vertebral column. Its attachment to the hyoid bone prevents the formation of a dewlap.
• The investing portion of the fascia is attached behind to the ligamentum nuchæand to the spinous process of the seventh cervical vertebra
Superior attachments and relations
• Above, the fascia is attached to the superior nuchal line of the occipital bone, to the mastoid process of the temporal bone, and to the whole length of the inferior border of the body of the mandible.
• Opposite the angle of the mandible the fascia is very strong, and binds the anterior edge of the Sternocleidomastoideus firmly to that bone.
• Between the mandible and the mastoid process it ensheathes the parotid gland—the layer which covers the gland extends upward under the name of the parotideomasseteric fascia and is fixed to the zygomatic arch.
• From the part which passes under the parotid gland a strong band extends upward to the styloid process, forming the stylomandibular ligament.
• Two other bands may be defined: the sphenomandibular and the pterygospinous ligaments.
• The pterygospinous ligament stretches from the upper part of the posterior border of the lateral pterygoid plate to the spinous process of the sphenoid.
• It occasionally ossifies, and in such cases, between its upper border and the base of the skull, a foramen is formed which transmits the branches of the mandibular nerve to the muscles of mastication.
Inferior attachments and relations
• Below, the fascia is attached to the acromion, the clavicle, and the manubrium sterni.
• Some little distance above the last it splits into two layers, superficial and deep.
• The former is attached to the anterior border of the manubrium, the latter to its posterior border and to the interclavicular ligament.
• Between these two layers is a slit-like interval, the suprasternal space (space of Burns); it contains a small quantity of areolar tissue, the lower portions of the anterior jugular veins and their transverse connecting branch, the sternal heads of the Sternocleidomastoidei, and sometimes a lymph gland.
Processes
• The fascia which lines the deep surface of the Sternocleidomastoideus gives off the following processes
• A process envelops the tendon at the Omohyoideus, and binds it down to the sternum and first costal cartilage.
• A strong sheath, the carotid sheath, encloses the carotid artery, internal jugular vein, and vagus nerve.
• The prevertebral fascia extends medialward behind the carotid vessels, where it assists in forming their sheath, and passes in front of the prevertebral muscles.
• The pretracheal fascia extends medially in front of the carotid vessels, and assists in forming the carotid sheath.
The Triangles of the Neck
• The side of the neck presents a somewhat quadrilateral outline , limited, above, by the lower border of the body of the mandible, and an imaginary line extending from the angle of the mandible to the mastoid process; below, by the upper border of the clavicle; in front, by the middle line of the neck; behind, by the anterior margin of the Trapezius. This space is subdivided into two large triangles by the Sternocleidomastoideus, which passes obliquely across the neck, from the sternum and clavicle below, to the mastoid process and occipital bone above. The triangular space in front of this muscle is called the anterior triangle; and that behind it, the posterior triangle
THE POSTERIOR TRIANGLE OF THE NECK
• Using a simplified lateral view of the neck we can once again easily identify the Borders of the posterior triangle of the neck:
• Sternocleidomastoid anteriorly
• Trapezius posteriorly • Clavicle inferiorly
Roof of the posterior triangle
• Platysma and superficial layer of the deep cervical fascia (Only platysma covers the vulnerable spinal accessory nerve crossing the posterior triangle)
Floor of the posterior triangle• A muscular floor and consists
of the following muscles which are arranged, in order, from posterosuperior to anteroinferior:
• 1. Splenius capitis - ligamentum nuchae and upper thoracic spinous vertebrae to the mastoid process and occipital bone (draws head backward or to the respective side).
• 2. Levator scapulae - processes of C1-C4 to the superior aspect of the medial border of the scapula (elevates scapula).
• 3. Scalenus muscles • a. scalenus anterior - anterior
tubercles of the transverse cervical processes to the scalene tubercle of the 1st rib.
• b. scalenus medius - posterior tubercles of all of the transverse cervical processes to the first rib.
• c. scalenus posterior - posterior tubercles of the transverse cervical processes to the 2nd rib.
• All muscles of the posterior triangle, whether boundary or floor muscles, are enclosed by separate subdivisions of the deep investing fascia of the neck.
• The posterior triangle of the neck can be further subdivided into:
• Occipital triangle lying above the inferior belly of the omohyoid
• Supraclavicular (Omoclavicular) triangle inferior to this muscle.
BOUNDARIES OF THE OCCIPITAL TRIANGLE:
• Posterior Boundary: Trapezius m. • Anterior Boundary: Sternocleidomastoid m. • Inferior Boundary: Omohyoid m. • Floor: Splenius Capitus m, Levator Scapulae m,
Scalenus Medius, and a portion of Scalenus Anterior.
• Roof: superficial layer of Deep Investing Fascia.
CONTENTS OF THE OCCIPITAL TRIANGLE
• Spinal Accessory nerve (XI) - crosses the upper half of the triangle diagonally and, passing from the deep surface of sternocleidomastoid inferiorly on levator scapulae to reach the deep surface of trapezius, innervates sternocleidomastoid and trapezius
• Superficial cervical cutaneous branches of Cervical plexus - formed from ventral primary rami of spinal nerves C2-C4, which emerge from posterior border of sternocleidomastoid– Lesser Occipital (C2) – follows posterior border of SCM to
innervate the scalp behind and above the ear. – Great Auricular Nerve (C2,3) - crosses superficial to SCM and
innervates the skin over the parotid gland, angle of the jaw and the posterior ear
– Transverse Cervical Cutaneous Nerve of the neck (C2,3) - crosses SCM superficially and, is cutaneous for the skin of the front and side of the neck (anterior triangle).
• Supraclavicular Nerves (C3,4) - divides into medial, intermediate, and lateral branches, which supply sensation over the shoulder(from the sternoclavicular joint to the acromion process), lateral neck and anterior upper thoracic wall.
• Part of the occipital and parts of the transverse cervical and suprascapular arteries are also found in the occipital triangle
Some words about the Brachial Plexus and its relevance in the Occipital Triangle
The lower four cervical nerves (C5,C6,C7,C8) are found in the scalene gap (space between scalenus anterior and scalenus medius muscles) and they, along with the first thoracic nerve (T1), make up the brachial plexus. Cervical nerves C5, C6, join to form the superior (upper) trunk of the brachial plexus, and these nerves as well as part of the superior trunk are found in the occipital triangle.
BOUNDARIES OF THE SUPRACLAVICULAR (Omoclavicular) TRIANGLE
• Inferior Boundary: Clavicle. • Superior Boundary: inferior belly of Omohyoid
m. • Anterior Boundary: Sternocleidomastoid m. • Floor: Splenius Capitus m, Levator Scapulae m,
Scalenus Medius m, and a small portion of the Scalenus Anterior m.
• Roof: superficial layer of Deep Investing Fascia
CONTENTS OF THE SUPRACLAVICULAR (Omoclavicular) TRIANGLE
• Superior trunk of the brachial plexus - this trunk is formed by the union of C5 and C6 and two nerves come from this trunk. (Also present in Occipital Triangle)
• a. Suprascapular - through the suprascapular foramen to innervate supraspinatus and infraspinatus
• b. Nerve to subclavius - innervates subclavius• Middle trunk of the brachial plexus - this trunk is the
continuation of the anterior primary division of the 7th cervical nerve.
• Lower trunk of the brachial plexus - this trunk is formed from the anterior primary division of the 8th cervical and 1st thoracic nerves.
• Subclavian artery (3rd part) - the first part of the subclavian artery lies medial to scalenus anterior, the second part lies posterior to this muscle, and the third part lies lateral to the scalenus anterior. The thyrocervical trunk arises from the first part of the subclavian, and two of its several branches (transverse cervical, suprascapular), pass through both the supraclavicular and occipital triangles in route to their destinations. The transverse cervical supplies trapezius, subscapularis, levator scapulae and the rhomboids, while the suprascapular supplies supra and infraspinatus. Occasionally there are no branches from the third part of the subclavian. An exception is when the descending scapular (dorsal scapular) arises from the second or third part of the artery (deep part of the transverse cervical artery
• External Jugular Vein: Derived from the Following Overview of venous drainage in the head and neck. – Superficial Temporal and Maxillary veins unite to form
Retromandibular vein.– Retromandibular vein divides at angle of mandible into Anterior
and Posterior divisions.– Anterior division joins Facial Vein to form Common Facial vein
which drains into Internal Jugular vein.– Posterior division joins Posterior Auricular vein to form External
Jugular vein.– External Jugular vein descends across Sternocleidomastoid muscle
to drain into Subclavian vein.– Anterior Jugular vein forms from small veins below
mandible;descends to join Ext. Jugular vein above clavicle. After lying superficial to the sternocleidomastoid muscle, the external jugular vein descends to the anterior angle of the posterior triangle where it enters the subclavian vein.
Suboccipital triangle
• The suboccipital triangle is a region of the neck bounded by the following three muscles of the suboccipital group of muscles:
• Rectus capitis posterior major - above and medially
• Obliquus capitis superior - above and laterally
• Obliquus capitis inferior - below and laterally
• (Rectus capitus posterior minor is also in this region but does not form part of the triangle)
• It is covered by a layer of dense fibro-fatty tissue, situated beneath the Semispinalis capitis.
• The floor is formed by the posterior occipito-atlantal membrane, and the posterior arch of the atlas.
• In the deep groove on the upper surface of the posterior arch of the atlas are the vertebral artery and the first cervical or suboccipital nerve.
• The vertebral artery is accessed here in order to conduct angiography of the circle of Willis.
CONTENTS OF THE SUBOCCIPITAL TRIANGLE
1)Third part of vertebral artery2)Dorsal ramus of nerve C1-SUBOCCIPITAL NERVE3)Suboccipital venous plexus
• The purpose of these muscles is to provide fine motor function in movements of the head. The actions of trapezius, sternocleidomastoid and other larger muscles that move the head are refined by the relatively small suboccipital triangle muscles
