Lab 2: Axial Skeleton, Bone Landmarks, and Skeletal Muscles

A comprehensive vocabulary flashcard set covering anatomical terms, skull/vertebral landmarks, muscle fiber arrangements, and major axial muscles with their actions.

Process

A bony prominence or bump.

Ramus

An extension of a bone creating an angle with the rest of the structure.

Condyle

A smoooth, rounded eminence with cartilage for articulation.

Facet

A smooth flat surface.

Head (Bone Landmark)

An enlargement at the end of a bone.

Lamina

A sheet-like part.

Trochlea

A smooth, grooved articular process shaped like a pulley.

Neck (Bone Landmark)

Narrow connection between the epiphysis and diaphysis of a bone.

Trochanter

A large, rough rounded part.

Tuberosity

A smaller, rough rounded part.

Tubercle

A small, rough rounded part.

Spine (Bone Landmark)

A sharp projection.

Crest

A prominent ridge.

Line (Bone Landmark)

A low ridge.

Fossa

A hallow ranging from a narrow trench to a broad shallow depression.

Sulcus

A narrow groove.

Foramen

A rounded passageway.

Canal

A passageway.

Fissure

An elongated cleft.

Sinus (or Antrum)

A chamber within a bone.

Axial Skeleton

Consists of all the bones that form the body’s central axis, including the bones of the skull, the vertebral column, and the rib cage.

Appendicular Skeleton

Includes the bones of the upper and lower appendages, as well as bones used to attach them to the axial skeleton (arms, legs, hands, feet, shoulder and hip girdles).

Parallel Muscle Fibers

Muscle fiber organization where fasciculi are parallel to the long axis of the muscle, such as the biceps brachii.

Convergent Muscle Fibers

Muscle fiber organization where fasciculi extend over a broad area and converge on a common attachment site, allowing the muscle to pull in different directions.

Pennate Muscle Fibers

Muscle fiber organization where fasciculi form a common angle with the tendon; typically contains many more myofibrils than a parallel muscle and produces more force.

Unipennate

A pennate muscle arrangement where all muscle fibers are on the same side of the tendon.

Bipennate

A pennate muscle arrangement with muscle fibers on both sides of the tendon.

Multipennate

A pennate muscle arrangement where the tendon branches within the muscle.

Circular Muscle Fibers

Muscle fiber organization where fasciculi are arranged concentrically around an opening or a recess, decreasing the diameter upon contraction.

Origin

The end of a skeletal muscle that usually fastens to a relatively immovable or fixed part; usually proximal.

Insertion

The end of a skeletal muscle that connects to a movable part on the other side of the joint; usually distal.

Agonist (Prime mover)

Muscle acting to provide most of the force for movement.

Synergist

Muscle that assists the prime mover; may function to assist the motion of the prime mover or to stabilize a joint to make motion more effective.

Antagonist

Muscle that resists the action of the prime mover by causing movement in the opposite direction.

Orbicularis Oris

Head and neck axial muscle whose action is to constrict the mouth.

Orbicularis Oculi

Head and neck axial muscle whose action is to close the eye.

Masseter

Head and neck axial muscle whose action is to elevate the mandible and close the jaw.

Buccinator

Head and neck axial muscle whose action is to compress the cheeks.

Temporalis

Head and neck axial muscle whose action is to elevate the mandible.

Platysma

Head and neck axial muscle whose action is to tense the skin of the neck and depress the mandible.

Sternocleidomastoid

Vertebral column axial muscle whose actions include flexion and rotation in the opposite direction.

Scalenes

Anterior, middle, and posterior vertebral column muscles whose actions include elevating the first two ribs and flexion.

Splenius Capitis & Splenius Cervicis

Vertebral column muscles whose actions include extension (both), rotation, and lateral flexion (same side).

Semispinalis Capitis & Semispinalis Cervicis

Vertebral column muscles whose actions include extension (both) and lateral flexion (same side).

Erector Spinae

Vertebral column muscles whose actions include extension (all divisions – both) and lateral flexion (same side).

Trapezius

Vertebral column axial muscle whose primary action is extension.

External Intercostals

Vertebral column axial muscles whose action is to elevate the ribs.

Internal Intercostals

Vertebral column axial muscles whose action is to depress the ribs.

Quadratus Lumborum

Vertebral column axial muscle whose actions include depressing the ribs (both) and lateral flexion (same side).

Rectus Abdominis

Abdominal wall muscle whose actions include flexion (both) and lateral flexion (same side).

External Oblique Abdominis

Abdominal wall muscle whose actions include flexion (both), rotation (opposite direction), and lateral flexion (same side).

Internal Oblique Abdominis

Abdominal wall muscle whose actions include flexion (both), rotation (same side), and lateral flexion (same side).

Transversus Abdominis

Abdominal wall muscle whose primary action is compression.