lecture 1 muscle terms and disorders

Vocabulary flashcards covering key terms on muscle attachments, lever mechanics, fascicle arrangements, functional muscle groupings, and common lower-limb disorders presented in the lecture.

Tendon

Dense connective tissue cord that attaches muscle to bone (or occasionally to another muscle) and transmits the force of contraction.

Origin (Muscle)

The usually proximal, relatively fixed attachment point of a muscle to a bone.

Insertion (Muscle)

The usually distal, more movable attachment point of a muscle to a bone.

Sarcomere

The contractile unit of striated muscle; shortens during muscle contraction.

Biceps brachii

Two-headed arm muscle that flexes the elbow and supinates the forearm.

Triceps brachii

Three-headed arm muscle that extends the elbow joint.

Serratus anterior

‘Boxer’s’ or ‘hugging’ muscle that protracts and rotates the scapula; also helps elevate ribs when scapula is fixed.

Lever

A rigid bar (bone) that moves on a fixed point when a force is applied to overcome a load.

Effort

The force applied to a lever—supplied by muscle contraction.

Fulcrum

The pivot point of a lever system; typically a joint.

Load (Resistance)

The weight or force that is moved by a lever—often the weight of the body segment or an external object.

First-class lever

Lever with fulcrum between effort and load (e.g., atlanto-occipital joint when nodding).

Second-class lever

Lever with load between fulcrum and effort (e.g., plantar-flexion at the ball of the foot when standing on tiptoe).

Third-class lever

Lever with effort between fulcrum and load (e.g., elbow flexion by biceps brachii).

Fascicle

Bundle of skeletal muscle fibers surrounded by perimysium.

Parallel fascicular arrangement

Fascicles run alongside the long axis of the muscle; produces large range of motion (e.g., sartorius).

Fusiform muscle

Spindle-shaped muscle with expanded belly and tapered ends (e.g., biceps brachii).

Circular muscle

Fascicles arranged in concentric rings that close an opening (e.g., orbicularis oris).

Triangular (Convergent) muscle

Broad origin with fascicles converging toward a single tendon (e.g., pectoralis major).

Pennate muscle

Short fascicles attach obliquely to a central tendon, resembling a feather.

Unipennate

Pennate muscle with fascicles inserting into one side of the tendon (e.g., extensor digitorum longus).

Bipennate

Pennate muscle with fascicles inserting into both sides of a central tendon (e.g., rectus femoris).

Multipennate

Pennate muscle with several tendons and multiple rows of fascicles (e.g., deltoid).

Agonist (Prime mover)

Muscle chiefly responsible for producing a specific movement.

Antagonist

Muscle that opposes or reverses the action of an agonist.

Synergist

Muscle that assists a prime mover by adding extra force or reducing undesirable movements.

Plantar aponeurosis

Thick band of connective tissue spanning the sole of the foot from calcaneus to toes.

Plantar fasciitis

Inflammation or micro-tearing of the plantar aponeurosis, producing heel or sole pain.

Compartment syndrome

Painful condition caused by rising pressure within a fascial compartment, compromising blood flow and nerve function.

PRICE protocol

First-aid approach: Protection, Rest, Ice, Compression, Elevation—used to manage acute musculoskeletal injuries.

NSAID (Non-steroidal Anti-inflammatory Drug)

Medication such as ibuprofen or aspirin that reduces pain, fever, and inflammation without steroid hormones.