Head and Neck Anatomy (2nd copy) PDF

Scalp SCA moves as a singular unit on top of the pericranium Arteries are between 1st and 2nd layer Aponeurosis consists of occipitofrontalis muscle Its tone inhibits closure of blood vessels/skin in scalp lacerations → dee...

Scalp SCA moves as a singular unit on top of the pericranium Arteries are between 1st and 2nd layer Aponeurosis consists of occipitofrontalis muscle Its tone inhibits closure of blood vessels/skin in scalp lacerations → deep scalp wounds gape Superficial scalp wounds which don’t lacerate the whole way do not gape Moves scalp, wrinkles forehead, raises eyebrows Frontal belly - innervated by temporal branches, posterior belly - posterior auricular branch of facial nerve VII  Scalp Innervation: Trigeminal nerve [V] ○ V1 → Supratrochlear, supra-orbital ○ V2 → Zygomaticotemporal ○ Auriculotemporal Cervical plexus ○ Lesser occipital (C2-3) ○ Greater occipital (C2) Arterial Supply: Internal carotid (anteriorly only) ○ Supratrochlear ○ Supra-orbital External carotid (all the rest) ○ Superficial temporal ○ Posterior auricular ○ Occipital Facial Muscles Muscles of facial expression develop from 2nd pharyngeal arch therefore are all innervated by facial nerve [VII] Orbital Group Orbicularis oculi - close eyes Corrugator supercilli - eyebrow together Nasal Group Procerus - eyebrow downward Nasalis - transverse compresses nares, alar opens nares Depressor septi nasi - open nostrils Other Platysma Anterior/ superior/ posterior auricular Occipitofrontalis Facial Muscles Oral Group from 12 to 6 o’clock Levator labii superioris alaeque nasi Levator anguli oris Levator labii superioris Zygomaticus minor/major Risorius Buccinator (underneath) - suck cheek to teeth Depressor levator labii inferioris Depressor anguli oris Mentalis - pout  Facial Muscles - Innervation Facial Nerve [VII] arises from posterior cranial fossa, runs through the internal acoustic meatus (temporal bone) and exits via the stylomastoid foramen to give off its motor branches to the muscles of facial expression: Note Connected Bits + Eyes + Brain (back to this later) Nasal sinuses drain into the nasal cavity Middle ear is connected to the nasopharynx via the eustachian tube Oral cavity and nasal cavity are separated by the hard and soft palate Pharynx → Oesophagus ○ Nasopharynx - from nasal cavity via choanae ○ Oropharynx - from oral cavity via palatoglossal folds Larynx → trachea The Neck Relations and Key Features Relations: To the thorax via: thoracic inlet To the upper limbs via: axillary inlet Key Landmarks: C3-4: common carotid artery bifurcation → external/internal carotid arteries C5-6: transition between larynx/trachea and pharynx/oesophagus, between cricoid cartilage and 1st tracheal ring  Bony Bits Cervical Vertebrae Occipitoatlantal joint C1 (atlas) ○ Anterior and posterior arch (no vertebral body) Atlantoaxial joint C2 (axis) ○ Dens (odontoid process) Typical vertebrae: C3-7) ○ Transverse processes with transverse foramen housing vertebral arteries and veins (except C7) ○ Vertebral body (rectangle) and foramen (triangular) ○ Bifid spinous process - with nuchal ligament in between For view of C1 and C2: AP open mouth projection X-Ray  Jefferson Fracture Fracture of atlas through anterior/posterior arches 50% associated with other cervical spine injuries 33% associated with C2 fracture Danger of vertebral artery injury  Muscles - Overview Divided into anterior, lateral, and posterior cervical muscles, all paired Anterior Lateral Posterior Superficial Anterior, middle and Superficial Platysma posterior scalenes Splenius capitis Sternocleidomastoid Rectus capitus Splenius cervicis scalene Subclavius Longus capitus Suboccipital Suprahyoids Longus colli Rectus capitis posterior major + minor Digastric Obliquus capitus superior + inferior Mylohyoid Transversospinalis Geniohyoid Semispinalis capitis + cervicis Stylohyoid Rotatores cervicis Infrahyoids Interspinalis Sternohyoid Intertransversarii Sternothyroid Thyrohyoid Omohyoid  Anterior Cervical Muscles Superficial Platysma - covers everything like a sheet Sternocleidomastoid (SCM) - from the sternum and clavicle to the mastoid therefore 2 heads Subclavius Suprahyoids (from inferior to superior) Digastric - anterior and posterior belly Mylohyoid - molar to hyoid Geniohyoid - chin to hyoid Stylohyoid - styloid process Infrahyoids (named from inferior to superior) Sternohyoid Sternothyroid Thyrohyoid Omohyoid - wraps around IJV and attaches to scapula  Anterior Cervical Muscles Superficial Platysma - covers everything like a sheet Sternocleidomastoid (SCM) - from the sternum and clavicle to the mastoid therefore 2 heads Subclavius Suprahyoids (from inferior to superior) Digastric - anterior and posterior belly Mylohyoid - molar to hyoid Geniohyoid - chin to hyoid Stylohyoid - styloid process Infrahyoids (named from inferior to superior) Sternohyoid Sternothyroid Thyrohyoid Omohyoid - wraps around IJV and attaches to scapula Lateral Cervical Muscles Rectus capitus Longus capitus Longus colli Scalenes All originate from transverse process then attach to: ○ First rib - anterior and middle scalenes ○ 2nd rib - posterior scalene Above the anterior scalene you can find: ○ Phrenic n. ○ Branches of thyrocervical trunk (suprascapular and transverse cervical a.) ○ Subclavian vein Between the anterior/middle scalenes you can find: ○ Brachial plexus ○ Subclavian artery Lateral Cervical Muscles Rectus capitus Longus capitus Longus colli Scalenes All originate from transverse process then attach to: ○ First rib - anterior and middle scalenes ○ 2nd rib - posterior scalene Above the anterior scalene you can find: ○ Phrenic n. ○ Branches of thyrocervical trunk (suprascapular and transverse cervical a.) ○ Subclavian vein Between the anterior/middle scalenes you can find: ○ Brachial plexus ○ Subclavian artery  Posterior Cervical Muscles (low yield) Superficial Splenius capitis Splenius cervicis scalene Suboccipital Rectus capitis posterior major + minor Obliquus capitus superior + inferior Transversospinalis Semispinalis capitis + cervicis Rotatores cervicis Interspinalis Intertransversarii  Cervical Cross Section and Fascias (HY) 1 Superficial cervical fascia Deep cervical fascia is split into Prevertebral fascia → endothoracic fascia and axillary sheath Pretracheal fascia → pericardium ○ Pharynx, larynx, oesophagus, trachea ○ Thyroid/parathyroid ○ Recurrent laryngeal n. ○ Strap muscles Carotid Sheath ○ Common carotid, IJV, CNX ○ Pierced by glossopharyngeal n. And ansa cervicalis ○ Connected by alar fascia Investing Layer ○ Traps and SCM Note: pre-... fascia because if you were to try to get to the vertebra, you would hit the fascia first Goitre Complications Compression of: Larynx → dysphonia Trachea → cough and dyspnoea Oesophagus → dysphagia SVC → superior vena cava syndrome (pemberton’s) Cervical Connective Tissue Injury Also called cervical strain/sprain Injuries to muscles, tendons, ligaments of cervical spine resulting from trauma Characteristic of whiplash injury Again Note Connected Bits + Thyroid Nasal sinuses drain into the nasal cavity Middle ear is connected to the nasopharynx via the eustachian tube Oral cavity and nasal cavity are separated by the hard and soft palate Pharynx → Oesophagus ○ Nasopharynx - from nasal cavity via choanae ○ Oropharynx - from oral cavity via palatoglossal folds Larynx → trachea  Cervical Plexus In the Posterior Triangle of the neck Cutaneous Branches Anterior rami (curls around SCM) Posterior rami Lesser occipital (C2) Greater occipital (C2) Great auricular (C2-3) Dorsal rami of C3, 4, 5 Transverse cervical (C2-3) Supraclavicular (C3-4) Muscular Branches C1 (travels w/ hypoglossal n) Suprahyoids Ansa Cervicalis (C1-3) Straps (sternohyoid, sternothyroid), omohyoid Phrenic (C3-5) Diaphragm and pericardium Segmental branches (C1-4) Anterior/middle scalenes Other branches Other cervical muscles Triangles of the Neck Anterior Δ: mandible, SCM, midline Associated with structures between head and thorax Posterior Δ: clavicle, SCM, trapezius Associated with axillary inlet (upper limb structures) Triangles of the Neck Anterior Δ: mandible, SCM, midline Associated with structures between head and thorax Structures: Midline structures: hyoid bone, larynx, thyroid/parathyroid, oesophagus Carotid sheath: carotid a. Bifurcation, internal/external jugular v., CNX Glossopharyngeal and hypoglossal n. Spinal accessory n. ← pic is lateral to medial Triangles of the Neck Posterior Δ: clavicle, SCM, trapezius Associated with axillary inlet (upper limb structures) Structures: Accessory n. [XI] - innervates SCM and trapezius muscles. Very superficial so commonly damaged, presenting as: ○ Issues with rotating neck (SCM) or shrugging shoulders (trap) against tension ○ Vague pain in left shoulder Omohyoid m. splits triangle into supraclavicular and occipital regions Subclavian a. Comes up just at the base (between anterior and middle scalenes) ← pic is lateral to medial