Anatomy of the Abdomen and Pelvis

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Questions and Answers

What is the primary nerve responsible for the motor innervation of the trapezius muscle?

Dorsal scapular nerve

Accessory nerve (XI) (correct)

C3-C4 nerve roots

Thoracodorsal nerve

Which muscle is primarily responsible for extending, adducting, and medially rotating the humerus?

Rhomboid major

Latissimus dorsi (correct)

Levator scapulae

Trapezius

Which muscle originates from the spinous processes of T2 to T5?

Latissimus dorsi

Rhomboid minor

Levator scapulae

Rhomboid major (correct)

What muscle action is primarily associated with the upper fibers of the trapezius?

Elevates scapula Signup and view all the answers

Which of the following muscles assists in retracting (adducting) the scapula?

Rhomboid major Signup and view all the answers

In terms of innervation, which of the following muscle groups is primarily innervated by the dorsal scapular nerve?

Rhomboid major and minor Signup and view all the answers

Which structure serves as the origin point for the levator scapulae muscle?

Transverse processes of C1 to C4 Signup and view all the answers

What is the primary function of the lower fibers of the trapezius muscle?

Depresses the scapula Signup and view all the answers

What is the primary origin of the Iliocostalis thoracis muscle?

Angles of the lower six ribs Signup and view all the answers

To which region does the Longissimus capitis muscle primarily insert?

Posterior margin of the mastoid process Signup and view all the answers

Which muscle blends with the Iliocostalis in the lumbar region?

Longissimus thoracis Signup and view all the answers

What is the insertion point for the Spinalis cervicis muscle?

Spinous process of C2 (axis) Signup and view all the answers

Which of the following muscles is associated with the lumbar area?

Iliocostalis lumborum Signup and view all the answers

What region does the origin of the Iliocostalis lumborum muscle include?

Sacrum and spinous processes of lumbar vertebrae Signup and view all the answers

Which of these muscles is located nearest to the actual spine?

Spinalis muscle Signup and view all the answers

What is the origin of the Longissimus cervicalis muscle?

Transverse processes of upper 4 or 5 thoracic vertebrae Signup and view all the answers

What is the primary function of the external urethral sphincter?

Compresses the membranous part of the urethra Signup and view all the answers

Where does the deep transverse perineal muscle insert?

Perineal body Signup and view all the answers

Which nerve innervates both the external urethral sphincter and the deep transverse perineal muscle?

Perineal branches of the pudendal nerve Signup and view all the answers

What is the origin of the compressor urethrae muscle?

Ischiopubic ramus Signup and view all the answers

What is a significant function of the sphincter urethrovaginalis in women?

Acts as an accessory sphincter of the urethra Signup and view all the answers

In what region do the erectile structures associated with the superficial perineal pouch develop?

Subcutaneous perineal space Signup and view all the answers

Which muscle is responsible for stabilizing the position of the perineal body?

Deep transverse perineal muscle Signup and view all the answers

Which function is associated with the compressor urethrae in women?

Serves as an accessory sphincter of the urethra Signup and view all the answers

Which muscle primarily assists in holding the head of the femur in the acetabulum?

Piriformis Signup and view all the answers

What is the primary action of the Coccygeus muscle?

Supports pelvic viscera Signup and view all the answers

Which of the following muscles forms the majority of the pelvic diaphragm?

Levator ani Signup and view all the answers

Which muscle has its proximal attachment at the ischial spine?

Coccygeus Signup and view all the answers

What is a function of the Obturator internus muscle?

Rotates the thigh laterally Signup and view all the answers

Which nerve innervates the Levator ani muscle?

Nerve to levator ani Signup and view all the answers

Which muscle is most closely associated with the action of abducting the thigh?

Piriformis Signup and view all the answers

Which of the following muscles is indirectly involved in supporting pelvic viscera?

Coccygeus Signup and view all the answers

Which of the following muscles primarily functions in the medial rotation and flexion of the humerus?

Pectoralis major Signup and view all the answers

What is the primary role of scalene muscles within the thorax?

Elevating the ribs during forced inspiration Signup and view all the answers

What is the specific origin of the pectoralis major muscle?

Medial half of clavicle and anterior surface of sternum Signup and view all the answers

Which nerve innervates the pectoralis minor muscle?

Medial pectoral nerves Signup and view all the answers

What is the main function of the subclavius muscle?

Stabilize the sternoclavicular joint Signup and view all the answers

Which muscle assists in protracting the scapula and depressing the shoulder's tip?

Pectoralis minor Signup and view all the answers

Which action is NOT associated with the pectoralis major muscle?

Elevation of the ribs during expiration Signup and view all the answers

Which of the following statements about the thoracic muscles is true?

Accessory muscles of respiration include pectoralis major and minor. Signup and view all the answers

Study Notes

Muscles of the Back

Superficial Group Innervation: Primarily innervated by anterior rami of spinal nerves.
Trapezius:
- Origin: Superior nuchal line, ligamentum nuchae, and spinous processes of C7 to T12.
- Function: Rotates scapula during humeral abduction, elevates, adducts, and depresses scapula.
Latissimus Dorsi:
- Origin: Spinous processes of T7-L5, sacrum, iliac crest, ribs 10-12.
- Function: Extends, adducts, and medially rotates the humerus.
Rhomboids (Major and Minor):
- Origin: Major - spinous processes of T2-T5; Minor - lower portion of ligamentum nuchae and spinous process of C7-T1.
- Function: Retracts (adducts) and elevates scapula.
Levator Scapulae:
- Origin: Transverse processes of C1 to C4.
- Function: Elevates the scapula.

Mnemonic for Back Muscles

Mnemonic: I Like Standing
- I: Iliocostalis
- Like: Longissimus
- Standing: Spinalis

Muscles of the Thorax

Axio-appendicular Muscles: Extend from the thoracic cage to the bones of the upper limb; also act as accessory muscles of respiration.
Scalene Muscles:
- Function as accessory muscles of respiration and stabilize the vertebral column.

Muscles of the Pectoral Region

Pectoralis Major:
- Origin: Medial half of the clavicle, sternum, and costal cartilages.
- Function: Medial rotation, adduction, and flexion of the humerus at the shoulder joint.
Pectoralis Minor:
- Origin: Anterior surfaces of the third to fifth ribs.
- Function: Depresses and protracts the scapula.
Subclavius:
- Origin: Rib 1 at junction with costal cartilage.
- Function: Stabilizes the sternoclavicular joint; depresses the tip of the shoulder.

Muscles of the Pelvis

Obturator Internus:
- Origin: Pelvic surfaces of the ilium and ischium, obturator membrane.
- Function: Rotates the thigh laterally.
Piriformis:
- Origin: Pelvic surface of S2-S4 segments.
- Function: Laterally rotates and abducts the thigh.
Coccygeus:
- Origin: Ischial spine.
- Function: Supports pelvic viscera and flexes coccyx.
Levator Ani:
- Comprises puborectalis, pubococcygeus, and iliococcygeus.
- Function: Forms the pelvic diaphragm, supports pelvic viscera.

Deep Perineal Pouch Muscles

External Urethral Sphincter:
- Origin: From the inferior ramus of the pubis.
- Function: Compresses the membranous urethra.
Deep Transverse Perineal Muscle:
- Function: Stabilizes the perineal body.
Compressor Urethrae:
- Function: Accessory sphincter of the urethra in women.
Sphincter Urethrovaginalis:
- Function: Accessory sphincter of the urethra and may assist in vagina closure.

General Anatomy Notes

Rectus Sheath and Linea Alba: Key structures in abdominal wall support.
Umbilical Ring: Important for understanding abdominal anatomy.
Interrelation of Muscles: Understanding muscle origins, insertions, and functions is crucial for grasping movement mechanics.

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Description

This quiz covers the structures and functions of the abdomen and pelvis, focusing on components like the rectus sheath, umbilical ring, and pelvic floor injuries. It assesses knowledge of the superficial and deep muscle groups of the back and their innervation. Test your understanding of this essential anatomy!