The Upper Limb and Facial Musculature

The muscles of your head and some of the muscles of your neck are innervated by ____ ______.

____ groups of facial muscles are traditionally identified by their innervation and function.

All of the upper limb muscles are innervated by the ____ _____, a combination of ventral rami from __-__.

Unlike the facial muscles, they are instead usually grouped by function as follows:

•Movers of the scapula
•Extrinsic muscles of the shoulder
•Intrinsic (rotator cuff) muscles of the shoulder
• Flexors of the elbow
• Extensors of the elbow
• Flexors of the wrist
• Extensors of the wrist

The Upper Limb and Facial Musculature

Remember that many of the muscles within each of the 7 groups above have a common attachment and / or common function. If you can remember them in ____, you will have a better chance at recalling them. Also, don’t forget that you’re carrying these muscles around with you. They may come in handy when you want to study.

Note that the attachments and actions of each muscle are summarized in table 7.3 of your textbook. The information provided here is not as precise, but will suffice.

The Facial Muscles

Muscles of Mastication

Innervated by the trigeminal (CN _), the masseter and temporalis muscles are responsible for ____ the jaws.
These can be felt when clenching the jaw.

The other group are the pterygoids. These muscles are ____ to your jaw and move it ____ and from side to side.

What are the muscles responsible for chewing and swallowing?

The Facial Muscles

Muscles of Facial Expression

There are numerous named muscles of facial expression that help us move our faces. All of these muscles are innervated by the facial nerve (CN __).

These muscles are unique in being attached to the ___ rather than only to bone.

What are the muscles responsible for facial expressions?

The Facial Muscles

Cranial Neck Muscles

The neck is a region of transition from cranial nerves to ____ nerves. Hence, some muscles, like the sternocleidomastoid and trapezius muscles are innervated by the spinal accessory nerve (CN __).

The deeper neck muscles are innervated by spinal nerves and will be considered in the next lab.

What are the neck muscles that move the head?

Movements of the Scapula

_______: The scapula is pulled laterally, as when extending the arm for something out of reach.

_______: The scapula is pulled medially, as when pulling your shoulders back.

_______: The scapula is moved superiorly, as when shrugging the shoulders.

________: The scapula is moved inferiorly, as when carrying a heavy suitcase.

Upper Limb Muscles: Reminder!!!

1. Glenohumeral motions:

2. Humeroulnar motions:

3. Radial motions:

4. Wrist motions:

5. Metacarpophalangeal joints:

6. Interphalangeal joints:

Upper Limb Muscles: Movers of the Scapula

The pectoral girdle forms a very mobile connection to the body. Several muscles move, and just as important, stabilize the ______.

The trapezius has a broad origin (proximal attachment) from the ____ _____ ____ to T12, and it’s insertion (distal attachment) is the ____ and _____ of the scapula.

Its fascicles travel in several directions, are capable of ____, ______ or _____ the scapula, depending on which part of the muscle is used. Also, since it attaches to the skull, each trapezius muscle can laterally flex the ____.

Upper Limb Muscles: Movers of the Scapula

The pectoralis minor (and the insignificant subclavius) ____ the scapula. The pectoralis minor attaches from the _-_ ribs to the _____ process.

Protraction of the scapula is produced by the ___ ______. This muscle is often called “the boxer’s muscle.” Can you guess why? It attaches from the lateral surface of the ___ to the deep surface of the ____.

The levator scapulae muscle ____ the scapula and the rhomboids (major & minor) _____ the scapula. The levator scapulae muscles attaches from the _____ vertebra and the rhomboids attach from the _____ vertebra to the scapula.

What muscles are grouped as "movers" of the scapula?

Upper Limb Muscles: The Shoulder

Two Groups of Movers of the Shoulder:

There are two groups of muscles that originate on the scapula and cross the _______ joint: those that attach at the shaft of the humerus (_____ muscles) and those that attach more proximally near the head of the humerus (the _____ muscles).

Humeral Shaft Muscles (The Extrinsic Muscles)

These are ____ muscles that produce the major movements of the upper arm. They include: the deltoid, pectoralis major, coracobrachialis, and latissimus dorsi. All have their distal attachment on the shaft of the _____.

The deltoid’s attachment can be easily felt. Follow your clavicle to your acromion around to the spine of your scapula. The muscle is often considered to have ___ parts according to these three attachments.
The ____, _____, and _____ deltoid are responsible for flexion, abduction, and extension of the humerus, respectively.

The coracobrachialis begins at the ____ process and attaches to the humeral shaft. It ____ the humerus.

Upper Limb Muscles: The Shoulder

Humeral Shaft Muscles (The Extrinsic Muscles)

The pectoralis major’s attachment begins at the ____ and ____. It inserts on the _____ _____. The primary action of the pectoralis major is to ____ the humerus.

Notice that the action of the clavicular part of the muscle would have a different action than the portion originating from the costal cartilages. Like most muscles, the various muscle fascicles can be used independently to provide the proper motion.

The latissimus dorsi and its partner, ____ major, extend the humerus as when ____ a boat. They also medially ___ the humerus.

The figure illustrates the huge attachment of the latissimus along the thoracic, lumbar and sacral vertebrae. The teres major begins at the inferior angle (point) of the scapula. They share an insertion with the pectorals major at the _____ _____.

Upper Limb Muscles: The Shoulder

Humeral Head Muscles (The Intrinsic Muscles)

Four muscles originate at the scapula and insert to the proximal humerus. These form the “___ ___,” a tendinous support that ____ the humeral head in the shallow glenoid cavity of the scapula.

Three of the muscles attach from the posterior/dorsal surface of the scapula and insert on the ____ ____ of the humerus.
These are the supraspinatus, the infraspinatus, and the teres minor.

Collectively, their action is to rotate the humerus ____. Supraspinatus lies within the _____ fossa, and infraspinatus and teres minor lie within the ______ fossa.

The subscapularis is the single muscle that originates in the _____ fossa and attaches to the ____ ____ of the humerus. It ____ rotates the humerus.

What muscles are grouped as "movers" of the shoulder?

Which are extrinsic and which are intrinsic?

Upper Limb Muscles: The Brachium

Two “compartments” are found in the brachium. The anterior compartment contains the flexors of the elbow and the posterior compartment contains its extensors.

The Anterior (Flexor) Compartment:

The brachialis originates at and lies against the anterior humerus, and it extends to the ___ _____.

The biceps brachii, so named for its two “heads,” originates at the coracoid process (___ head) and supraglenoid tubercle (____ head). The biceps muscles attach to the ____ _______.

Upper Limb Muscles: The Brachium

The Posterior (Extensor) Compartment

The triceps muscle lies in the posterior compartment of the brachium. Its three heads originate from the infraglenoid tubercle (___ head) and posterior humerus (___, ___ heads). They combine to form a common tendon that inserts on the ____ process.

Also note the insignificant ____ muscle at the elbow which assists the triceps.

Upper Limb Muscles: The Antebrachium

Two compartments separate the anterior and posterior muscles of the antebrachium.

The anterior compartment contains the ___ of the wrist and digits as well as a muscle that ____ the forearm.

The posterior compartment mostly contains ____ of the wrist and digits along with a ____ of the forearm.

The names of these muscles are very logical. Be sure you understand the relationship between the muscle names and their actions.

Upper Limb Muscles: The Antebrachium

The Anterior Compartment of the Antebrachium

The _ anterior compartment muscles of the antebrachium originate from the ___ _____ of the humerus.

The largest and deepest of these is the flexor digitorum superficialis. It is a flat muscle that sends tendons to the phalanges, thus allowing for ____ of the digits.

Overlying this flat muscle are 4 round muscles. From lateral to medial they are: pronator teres, flexor carpi radialis, palmaris longus, and flexor carpi ulnaris.

The pronator teres inserts on the ___ shaft and ____ the antebrachium.

The flexor carpi radialis and the flexor carpi ulnaris attach to ____ on their respective sides of the wrist, which they ___.

Palmaris longus attaches to a thick connective tissue of the hand, the palmar _______. This tissue holds the skin of the palm in place (unlike the freely mobile skin on the dorsal surface of your hand).

Contraction of palmaris longus stabilizes the palm when _____ an object. 10-15% of the population may be lacking this muscle.

Upper Limb Muscles: The Antebrachium

The Posterior Compartment

The _ posterior compartment muscles of the antebrachium all originate from the ____ _____.

The most lateral of these is the brachioradialis. Its inserts on the distal ___ and functions is to ___ the forearm.

All others in the posterior compartment are ______.

From lateral to medial, there are 5 muscles:

• extensor carpi radialis (longus and brevis), which attaches to the base of the metacarpals _ & _ and extends the ___.

• extensor digitorum, which attaches to the digits (_-_) and extends them.

• extensor digiti minimi, which extends your “____” finger when you drink tea. It attaches to the __ digit.

• extensor carpi ulnaris, which attaches to the base of the ___ _ and extends the __.

Upper Limb Muscles: The Antebrachium

The Posterior Compartment

A final group of muscles lies deep the those mentioned above and has a common attachment on the ____.

One of these muscles, the supinator, attaches to the radius from the humerus’ ____ epicondyle and the ___.

The supinator is ____ around the radius so as to “unwind” when contracting, thus turning the palm forward in the movement of supination (in opposition to the ___ ____).

The remaining small deep muscles extend or abduct the ___ and _ __. They, along with the muscles within the hand will not be considered in this lab.