Exam 2

Question 1

Sternocleidomastoid (SCM)

Location, bone attachment sites, innervation, and action

Identify the superficial muscles of the neck (sternocleidomastoid, platysma,trapezius) p. 1010,
Table 9-2

Answer 1

Origin= lateral surface of mastoid process of temporal bone

Insertion=
sternal head: anterior surface of manubrium
Clavicular head: superior surface of medial third of clavicle
Innervation= spinal acessory nerve (CN XI, motor)
Main Action=
unilateral contraciton: laterally flexes neck and rotates it
bilateral contraction= extends neck at atlantooccipital joints, flexes cervical vertebrae so chin appraoches manubrium, extends superior cervical vertebrae

Question 2

Platysma

Location, bone attachment sites, innervation, and action

Identify the superficial muscles of the neck (sternocleidomastoid, platysma,trapezius) p. 1010,
Table 9-2

Answer 2

on anterior side of neck
Origin= inferior border of mandible, skin
Insertion= fascia covering superior parts of deltoid and pectoralis major
Innervatiin= cervical branch of facial nerve (CN VII)
Action= draws corner of mouth interioly and widnes for expressions of sadness and fright

Question 3

Trapezius

Location, bone attachment sites, innervation, and action

Identify the superficial muscles of the neck (sternocleidomastoid, platysma,trapezius) p. 1010,
Table 9-2

Answer 3

extrinsic muscle, posterior superior superficial surface of back
origin= medial third of superior nuchal line, external occipital protuberence, nuchal ligament
Insertion= lateral third of clavicle, acromion, spine of scapula
Innervation= spinal acessory nerve (CN XI; motor)
Main action= elevates, retracts, and rotates scapula inferioly

Question 4

Anterior, Middle, Posterior scalenes

Identify the scalene muscles p.1013

Answer 4

Anterior scalene: O= anterior tubercles of transverse processe of c3-c6 vertebrae.
I= 1st rib.
Insertion= cervical spinal nerves c4-c6
A= flexes neck latearlly, elevates 1st rib during inspiration

Middle Scalene. O= posterior tubercles of transverse processes of c4-c7
I= superior surface of 1st rib
I= anterior rami of cervical spinal nerves
Action= felxes neck laterally, elevevates 1st rib during inspiration

Posterior scalene: O= posterior tubercles of transverse processes of c4-c6 vertebrae
I= external border of 2nd rib
I= naterior rami of cervical spinal nerves c7 and c8
Action= flexes neck laterally, elevates 2nd rib during inspiration

Question 5

Suprahyoid muscles O, I, I, A

Identify the suprahyoid and infrahyoid muscles Table 9.3, p. 1021. Identify the bone
attachments and actions of each muscle (e.g. elevate hyoid, depress hyoid)

Answer 5

Myolohyoid:
O= myolohyoid line of mandible. I= myolohyoid raphe and body oh hyoid. I= nerve to myolohyoid. A= elevates hyoid during swallowing/speaking

Geniohyoid:
O= inferior mental spine of mandible. I= body of hyoid. I= C1 hypoglossal nerve. A= pulls hyoid anterosuperioly.

Stylohyoid:
O= styloid process of temporal bone. I= body of hyoid. I= stylohyoid branch of facial nerve. A= elevates and retracts hyoid

Digastric:
O= digastric fossa of mandible (anterior belly), mastoid notch of temporal bone (posterior bely), I= intermediate tendon to body and greater horn of hy. I= nerve to myolohyoid (anterior belly), digastric fance of facial nerve (posterior belly). A= works wtih infrahyoid muscles

Question 6

Infrahyoid muscles O,I,I,A

Identify the suprahyoid and infrahyoid muscles Table 9.3, p. 1021. Identify the bone
attachments and actions of each muscle (e.g. elevate hyoid, depress hyoid)

Answer 6

Question 7

Describe the location and function of the carotid body and carotid sinus p. 1019

Answer 7

carotid sinus contains baroreceptors to detect blood pressure Located Dilation of the proximal part of the internal carotid artery

Carotid body contains chemoreceptors to detect blood oxygen levels. Located in a septum on the medial (deep) side of the bifurcation of the common carotid artery

Question 8

Prevertebral muscles + actions

Identify the prevertebral muscles and their actions p. 1031. Table 9.4

Answer 8

Longus colli= Bilateral action: flexion of neck
Unilateral action:
lateral flexion; rotation of neck to opposite side

longus capitis= Action: Flexion of head and neck (bilateral)
Lateral flexion of head and neck (unilateral)

rectus capitis anterior= Flexion of head at atlantooccipital joint (bilateral)
Lateral flexion of head (unilateral)

rectus capitis lateralis= lateral flexion of the head

Question 9

Describe the structure of the rib cage and sternum. Identify the sternal angle and its relationship
to ribs and vertebrae. Distinguish between true, false, and floating ribs