3D Models Related Images

Muscular and Osseous Relationships

Surgical Correlation


A, The skin and subcutaneous tissues have been removed to expose the parotid gland and the facial nerve branches that course deep to the parotid gland on their way to the facial muscles. The masseter muscle has two heads: a more superficial anterior head, which passes downward to the lateral surface of the angle of the jaw, and a deeper posterior head, which arises from the medial surface of the zygomatic arch and passes to the mandibular body. The sternocleidomastoid attaches to the lateral part of the superior nuchal line and mastoid process, descends in an anterior direction, and is crossed by the greater auricular nerve. The temporalis fascia attaches to the upper surface of the zygomatic arch. The trapezius muscle attaches to the medial part of the superior nuchal line. The posterior triangle of the neck, located between the sternocleidomastoid and trapezius, has the semispinalis capitis, splenius capitis, and levator scapulae in its floor. The terminal branches of the occipital artery and the greater occipital nerve reach the subcutaneous tissues by passing between the attachment of the trapezius and sternocleidomastoid muscles to the superior nuchal line. B, Enlarged view. The facial nerve branches are exposed along the anterior edge of the parotid gland. C, The parotid gland has been removed to expose the facial nerve and its branches distal to the stylomastoid foramen. The nerve passes lateral to the styloid process, the external carotid artery, and mandibular neck. The superficial and deep heads of the masseter muscle are exposed. This lower end of the sternocleidomastoid muscle has been reflected posteriorly by dividing its attachment to the clavicle and sternum. The superficial temporal artery ascends in front of the ear. D, The upper part of the mandibular ramus and the lower part of the temporalis muscle and its attachment to the coronoid process have been removed while preserving the inferior alveolar nerve. The infratemporal fossa is located medial to the mandible and on the deep side of the temporalis muscle. The upper and lower heads of the lateral pterygoid, which insert along the temporomandibular joint, and the superficial head of the medial pterygoid, which extends from the lateral pterygoid plate to the angle of the jaw, have been exposed. The structures in the infratemporal fossa include the pterygoid muscles, branches of the mandibular nerve, the maxillary artery, and the pterygoid venous plexus. The sternocleidomastoid muscle has been reflected out of the exposure to expose the splenius capitis muscle. E, Posterolateral view. The splenius capitis has been reflected downward to expose the longissimus capitis, superior oblique, and semispinalis capitis. The occipital artery passes along the occipital groove on the medial side of the digastric groove. F, The longissimus capitis has been reflected downward to expose the rectus capitis posterior minor and major, which descend from the occipital bone to attach to the spinous process of C1 and C2, respectively; the superior oblique, which passes from the occipital bone to the transverse process of C1; and the inferior oblique, which extends from the spinous process of C2 to the transverse process of C1. The vertebral artery, in its ascent from C2 to C1, is exposed medial to the attachment of the levator scapulae to the C1 transverse process. The C1 transverse process is situated immediately behind the internal jugular vein and a short distance below and behind the jugular foramen. (Images courtesy of AL Rhoton, Jr.)