Muscle Anatomy: Origins, Insertions, Actions, and Innervations

Comprehensive flashcards covering muscle origins, insertions, actions, and innervations as described in the lecture notes.

What is the origin and insertion of the Trapezius muscle?

The origin includes the medial superior nuchal line, EOP, nuchal ligament, and SP $C7-T12$; the insertion is the lateral $1/3$ clavicle, acromion, and spine of the scapula.

What are the specific actions of the Trapezius muscle segments?

Descending = $ELEV$; Middle = $RETR$; Ascending = $DEPR$.

What nerve is responsible for the innervation of the Trapezius?

Cranial nerve $11$ (Accessory nerve).

What is the action of the Latissimus Dorsi in Open Kinetic Chain ($OKC$) and Closed Kinetic Chain ($CKC$)?

$OKC$ = shoulder $EXT$ and $ADD$; $CKC$ = pull body to arms.

What is the innervation of the Latissimus Dorsi?

Thoracodorsal nerve (nerve root $C6-C8$).

Where does the Rhomboid Minor originate and insert?

Origin: SP $C7-T1$ and nuchal ligament; Insertion: Medial end of the spine of the scapula.

What are the shared actions of Rhomboid Minor and Rhomboid Major?

$RETR$ and $ROT$ of the glenoid fossa inferiorly, and fixing the scapula to the thoracic wall.

What nerve innervates the Rhomboid Minor, Rhomboid Major, and Levator Scapulae?

Dorsal scapular nerve (nerve root $C5$).

What are the origin and insertion of the Rhomboid Major?

Origin: SP $T2-T5$; Insertion: From the medial end of the scapula spine to the inferior angle of the scapula.

What is the origin and action of the Levator Scapulae?

Origin: Posterior tubercles on $C1-C4$ TP; Action: $ELEV$ and $ROT$ of the glenoid fossa inferiorly.

What is the action and innervation of the Serratus Posterior Superior?

Action: $ELEV$ ribs for inspiration; Innervation: Intercostal nerve of ribs $2-5$.

What is the action and innervation of the Serratus Posterior Inferior?

Action: $DEPR$ of ribs for expiration; Innervation: Ventral rami of $T9-12$.

What are the bilateral and unilateral actions of the Splenius Capitis and Splenius Cervicis?

Bilateral = $EXT$; Unilateral = $IPL$ $SB$ and $ROT$.

What are the insertions for Splenius Capitis and Splenius Cervicis?

Splenius Capitis: Mastoid process and lateral $1/3$ of superior nuchal line; Splenius Cervicis: TP of $C1-C3$.

What is the general action and innervation of the Erector Spinae Group?

Action: Bilateral ($BL$) = trunk $EXT$, Unilateral ($UL$) = $IPL$ $SB$; Innervation: Dorsal rami.

Where does the Iliocostalis thoracis originate and insert?

Origin: Angles of lower ribs; Insertion: Angles of upper ribs.

Where is the Longissimus capitis inserted?

Mastoid process.

What are the origin and insertion of the Spinalis muscle?

Origin: SP $T10-12$; Insertion: Occiput and SP of upper thoracic.

What is the action of the Semispinalis Capitis?

Neck $EXT$ and $CL$ $ROT$.

What are the characteristics and actions of the Multifidus?

It spans $2-4$ segments, is located only in lumbar and sacral regions, and acts to $EXT$ the neck, $CL$ $ROT$, and stabilize the pelvis.

How do Rotatores Brevis and Rotatores Longus differ in their segment span?

Brevis spans $1$ segment, while Longus spans $2$ segments.

What is the action of the Intertransversarri muscles?

Lateral $SB$ and stabilization.

What is the action of the Interspinalis muscles?

$EXT$ and $ROT$.

What are the two types of Levator cestrum and their action?

Brevis (attaches to rib between segment) and Longus (skips a segment to the rib below); their action is respiration movement.

What is the origin and insertion of the Rectus Capitis Posterior Major?

Origin: SP of $C2$; Insertion: Lateral inferior nuchal line.

What is the origin and insertion of the Rectus Capitis Posterior Minor?

Origin: Posterior tubercle of $C1$; Insertion: Medial inferior nuchal line.

What are the origin and insertion of the Oblique Capitis Inferior?

Origin: SP of $C2$; Insertion: TP of $C1$.

What is the insertion of the Oblique Capitis Superior?

Between the superior and inferior nuchal line (lower space).

What is the innervation for the suboccipital muscles (Rectus Capitis and Oblique Capitis)?

Suboccipital nerve ($C1$ nerve root).

What is the OIAN for the Deltoids?

Anterior (clvaicular) part- unipenate

• O= lateral 1/3 of clavicle

• I= deltoid tuberosity

• A= FLX and IR

• INE= axillary nerve (C5-6)

Middle (acomial) part- multipenate

• O= acromion of scapula

• I= deltoid tuberosity

• A= ABD

• INE= axillary nerve (C5-6)

Posterior (spinal) part- unipenate

• O= spine of scapula

• I= deltoid tuberosity

• A= EXT and ER

• INE= axillary nerve (C5-6)

What are the OIAN of the supraspinatis muscle?

O= supraspinous fossa of scapula

I= superior facet of the greater tubercle

A= first 15 degrees of shoulder ABD

INE= suprascapular nerve (C5-6)

What is the OIAN of the infraspinatis?

O= infraspinous fossa

I= middle facet of the greater tubercle

A= ER

INE= suprascapular nerve (C5-6)

What is the OIAN of teres minor?

O= middle lateral border of the scapula

I= inferior facet of the greater tubercle

A= minor ER

INE= axillary nerve (C5-6)

WHat is the OIAN of the subscapularis muscle?

O= subscapular fossa

I= lesser tubercle

A= IR and ADD

INE= upper and lower subscapular nerves (both C5-6)

WHat is the OIAN of teres major?

o= posterior inferior angle of the scapula

I= medial crest of the intertubecular sulcus

A= ADD, IR, and slight EXT

INE= lower subscapular nerve (C5-6)

What is the OIAN for the Triceps, long head?

O= infraglenoid tubercle of scapula

I= proximal olecronon and forearm fasica

A= elbow EXT and steadies teh head of the humerus when the arm is ABD

INE= radial nerve (C6-8)

What is the OIAN of the serratus anterior?

O= external/lateral surface of ribs 1-8

I= anterior surface of the vetebral border of scapula

A= PRO, UR, and holds scapula tight against the thoracic wall

INE= long thoracic nerve (C5-7)

What is the OIAN of the pectoralis major?

O= anteior sternum, anteriomedial clavicle, superior 6 costal cartilages, and aponerosis of the external obliques

I= anterior lateral crest of the intertubercular groove

A= powerful ADD, but also PROT, DR, and IR

INE= lateral pectoral nerve (clavicular head) (C5-7)

part of the lateral pectoral nerve (just C7) and medial pectoral nerve (C8-T1) for the sternalcostal head

What is the OIAN for pec minor?

O= anterior surface of ribs 2-5

I= medial superior surface of the coracoid process of scapula

A= scapular setting= stabalizes scapula when reaching for something

INE= only medial pectoral nerve (C8-T1)

What is the OIAN of the subclavius muscle?

O= junction between the first rib and its costal cartilage

I= inferior middle 1/3 surface of the clavicle at the subclavian groove

A= DEPR and stabalize clavicle

INE= nerve to subclavius (C5-6)