lateral rotator group

(noun)

The externus and internus obturators, the piriformis, the superior and inferior gemelli, and the quadratus femoris.

Related Terms

  • gluteal group
  • adductor group
  • iliopsoas group

Examples of lateral rotator group in the following topics:

  • Muscles that Cause Movement at the Hip Joint

    • The four main groups of hip muscles are gluteal, adductor, iliopsoas, and lateral rotator, defined by the type of movement they mediate.
    • The muscles of the lateral rotator group are deeply located and as the name suggests, act to laterally rotate the thigh at the hip.
    • All of the lateral rotator group muscles originate from the pelvis and attach to the femur.
    • Piriformis - The piriformis is the most superior of the lateral rotator group muscles.
    • It is the most inferior of the lateral rotator group muscles, located below the gemelli and obturator internus.
  • Anterior Muscles

    • Serratus Anterior – The serratus anterior is located in the lateral wall of the chest.
    • Five muscles form the abdominal wall, divided into vertical and flat groups.
    • The flat muscles act to flex, laterally flex, and rotate the trunk.
  • Muscles of the Shoulder

    • Upper arm muscles will be discussed in a later section since they primarily promote forearm movement.
    • It retracts and rotates the scapula.
    • The lateral region assists in shoulder flexion when the shoulder is rotating, although it also assists the transverse abduction of the shoulder.
    • The rotator cuff is a group of four muscles that pull the ball of the humerus into the shallow socket of the scapula, adding required stability.
    • Serratus Anterior – The serratus anterior is located in the lateral wall of the chest.
  • Posterior Muscles

    • Posterior muscles are split into three groups depending on their physiological location.
    • Actions – The superior region supports the arm and elevates and rotates the scapula, the intermediate region retracts the scapula, and the inferior region rotates and depresses the scapula.
    • Two muscles in the superficial layer are responsible for rotation of the head.
    • Iliocostalis – The most laterally located of the three intermediate muscles.
    • Two muscles in the deep layer are responsible for maintenance of posture and rotation of the neck.
  • Neck Muscles

    • Omohyoid – Located laterally to the sternohyoid, the omohyoid muscle is split in two parts attached by a tendon.
    • Two muscles in the superficial layer are responsible for rotation of the head.
    • Iliocostalis – The most laterally located of the three intermediate muscles.
    • It controls adduction, abduction and rotation of the head, the intermediate region retracts the scapula, and the inferior region rotates and depresses the scapula.
    • Suprahyoid and infrahyoid muscle groups are named based on their location relative to the hyoid bone.
  • Muscles that Cause Movement at the Knee Joint

    • When the knee is fully extended the femur rotates slightly on the tibia to lock the joint into place, allowing for efficient load bearing.
    • The rectus femoris additionally facilitates rotation at the hip.
    • These muscles are sometimes termed the hamstring group.
    • Actions: Extends and laterally rotates at the hip, main action is flexing of the lower leg at the knee.
    • Actions: Laterally rotates the femur on the tibia “unlocking” the knee joint so that flexion can occur.
  • Femur (The Thigh)

    • Immediately lateral to the head is the neck, which connects the head with the shaft, narrower than the head the neck permits a greater range of movement at the hip joint.
    • Located superiorly on the main shaft, lateral to the joining of the neck, the greater trochanter is a projection to which the abductor and lateral rotator muscles of the leg attach.
    • Two rounded regions termed the medial and lateral condyles articulate with the tibia and at the most anterior projection the patella.
    • Finally, medial and lateral epicondyles lie immediately proximal to the condyles and are also regains where key internal knee ligaments attach.
  • Lever Systems

    • For example, moving arms or legs laterally away from the body is abduction, and bringing the limbs back to the midline is adduction.
    • Internal or medial rotation is specific to the shoulder or hip and brings the distal portions of the limbs inwards towards the midline.
    • Internal rotation can also move the humerus and femur inward.
    • External or lateral rotation is the opposite movement, pointing the distal portion of limbs as well as the humerus and femur away from the mid-line.
  • How Skeletal Muscles Produce Movements

    • Muscles are arranged in groupings of agonist, antagonist, and synergists that produce and modulate movement.
    • The biceps and triceps muscle groups are an example of an agonist/antagonist pair.
    • Muscles exist in groupings that work to produce movements by muscle contraction.
    • The majority of muscles are grouped in pairs, with an antagonist to each agonist muscle.
    • The muscles of the rotator cuff are also synergists in that they fix the shoulder joint allowing the bicepps brachii to exert a greater force.
  • Muscles of the Wrist and Hand

    • Actions – Rotates the thumb towards the palm, producing opposition and improving grip.
    • Actions - Rotates little finger towards the palm, producing opposition and improving grip.
    • Flexor Digiti Minimi Brevis – Located laterally to the digiti minimi.
    • The interossei muscles are located between the fingers; they can be split into two groups.
    • One other muscle in the hand is not easily grouped with the above categories.
Subjects
  • Accounting
  • Algebra
  • Art History
  • Biology
  • Business
  • Calculus
  • Chemistry
  • Communications
  • Economics
  • Finance
  • Management
  • Marketing
  • Microbiology
  • Physics
  • Physiology
  • Political Science
  • Psychology
  • Sociology
  • Statistics
  • U.S. History
  • World History
  • Writing

Except where noted, content and user contributions on this site are licensed under CC BY-SA 4.0 with attribution required.