Anatomy and Physiology Flashcards

A massage therapist is working with a client who reports numbness in the lateral forearm and thumb. Which nerve is most likely compressed, and at which anatomical landmark is compression most clinically significant?

Answer: Lateral antebrachial cutaneous nerve between the biceps tendon and brachioradialis

The lateral antebrachial cutaneous nerve, the terminal sensory branch of the musculocutaneous nerve, exits between the biceps tendon and brachioradialis at the elbow crease and innervates the lateral forearm and thumb-side skin. Compression here produces the described sensory pattern. The radial nerve at the spiral groove would cause wrist drop; the median nerve at the carpal tunnel primarily affects digits 1–3½ with motor deficits; the musculocutaneous nerve at the coracobrachialis is proximal and would also impair elbow flexion.

During the cardiac cycle, the aortic valve opens when left ventricular pressure exceeds aortic diastolic pressure. Which phase of the cardiac cycle does this mark the beginning of?

Answer: Rapid ventricular ejection

When left ventricular pressure surpasses aortic diastolic pressure (~80 mmHg), the aortic valve opens and rapid ventricular ejection begins — the phase in which ~70% of stroke volume exits quickly. Isovolumetric contraction precedes this event (both valves closed, pressure rising). Isovolumetric relaxation occurs after the aortic valve closes. Reduced ventricular filling is a diastolic phase.

Which of the following correctly describes the functional role of the zona glomerulosa of the adrenal cortex and the hormone it secretes in relation to massage therapy contraindications?

Answer: It secretes aldosterone, which regulates sodium retention; clients on fludrocortisone analogs may present with hypertension requiring gentler pressure application

The zona glomerulosa is the outermost adrenal cortex layer and exclusively secretes mineralocorticoids — primarily aldosterone — which promotes sodium and water retention in the renal collecting duct, elevating blood volume and pressure. Clients taking synthetic mineralocorticoids (fludrocortisone) for conditions like Addison's disease may have labile blood pressure, making positioning and pressure depth clinically relevant. Cortisol comes from the zona fasciculata; DHEA from the zona reticularis; epinephrine is secreted by the adrenal medulla, not the cortex.

The deep cervical fascia forms distinct layers enveloping neck structures. Which layer directly invests the trapezius and sternocleidomastoid muscles and forms the roof of the posterior triangle of the neck?

Answer: Investing layer

The investing (superficial) layer of deep cervical fascia encircles the entire neck, splitting to enclose both the trapezius and sternocleidomastoid. It forms the roof of the posterior cervical triangle — critical anatomical knowledge for cervical massage and lymphatic drainage work. The pretracheal layer surrounds the thyroid and trachea. The prevertebral layer covers the vertebral column and deep neck muscles. The carotid sheath is a distinct fascial tube containing the common carotid artery, internal jugular vein, and vagus nerve.

A client with a C7 nerve root compression would most predictably present with which combination of deficits?

Answer: Weakness of triceps and wrist flexors, loss of triceps reflex, and sensory loss over the middle finger

The C7 nerve root innervates the triceps (elbow extension), wrist flexors (via median contributions), and contributes to the triceps reflex (the classic C7 deep tendon reflex). Its sensory dermatome covers the middle (third) finger and dorsal mid-forearm. C6 affects the brachioradialis reflex and lateral forearm/thumb (choice A). C5 affects the deltoid, biceps reflex, and lateral arm (choice C). C8–T1 affects intrinsic hand muscles and medial digits (choice D).

In the context of fascia and connective tissue physiology, thixotropy refers to which property that is directly relevant to the mechanism of myofascial release?

Answer: The gel-to-sol transition of ground substance when sustained mechanical force is applied, reducing viscosity

Thixotropy is the property of certain gels (including the proteoglycan ground substance of fascia) to become less viscous (sol state) under sustained or repeated mechanical agitation and return to a more viscous gel state at rest. In myofascial release, slow, sustained compression is thought to exploit this property, temporarily liquefying the ground substance to allow fascial gliding and lengthening. Collagen remodeling (choice A) describes long-term adaptation (Wolff's law analogy for soft tissue). Elastic recoil (choice C) describes elastin properties. Piezoelectricity (choice D) is a separate phenomenon also attributed to collagen but distinct from thixotropy.