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Home , Genu recurvatum, Hammer toe

DEVIATIONS FROM OPTIMAL ALIGNMENT IN THE SAGITTAL PLANE

Foot and

1. Claw Toes • Claw toes is a deformity of the toes characterized by hyperextension of the metatarsophalangeal (MTP) joint, combined with flexion of the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints. • The abnormal distribution of weight may result in formation under the heads of the metatarsals or under the end of the distal phalanx. • Sometimes the proximal phalanx may subluxate dorsally on the metatarsal head. • may develop on the dorsal aspects of the flexed phalanges from constant rubbing on the inside of . • In essence, this deformity reduces the area of the BoS and, as a result, may increase postural sway and decrease stability in the standing position. • A few of the many suggested etiologies for this condition are as follows: the restrictive effect of shoes, a cavus-type foot, muscular imbalance, ineffectiveness of intrinsic foot muscles, neuromuscular disorders, and age-related deficiencies in the plantar structures.

2. Hammer Toes • Hammer is described as a deformity characterized by hyperextension of the MTP joint, flexion of the PIP joint, and hyperextension of the DIP joint. • Callosities (painless thickenings of the epidermis) may be found on the superior surfaces of the PIP joints over the heads of the first phalanges as a result of pressure from the shoes. • The tips of the distal phalanges also may show callosities as a result of abnormal weight-bearing. • The flexor muscles are stretched over the MTP joint and shortened over the PIP joint. • The extensor muscles are shortened over the MTP joint and stretched over the PIP joint. • If the long and short toe extensors and lumbrical muscles are selectively paralyzed, the intrinsic and extrinsic toe flexors acting unopposed will buckle the PIP and DIP joints and cause a .

Knee

1. Flexed Posture • Flexed knee standing posture can result from knee flexion . In flexed knee, the LoG shifts posteriorly to the axes of knee joint. This shift creates an external flexion moment at the knee joint, which is balanced by internal extension moment created by activity of quadriceps to maintain erect position. • The increase in muscle activity needed to maintain a flexed knee posture subjects the tibiofemoral and patellofemoral joints to greater-than-normal compressive stress and can lead to fatigue of the quadriceps femoris and other muscles if the posture is maintained for a prolonged period. • Knee flexed posture also results in increased activity of extensors, soleus and gastrocnemius.

POSTURAL ABNORMALITIES ­ ZAS Page 1 2. Hyperextended Knee Posture () • Hyperextension at the knee is usually caused either by limited dorsiflexion at the ankle or by a fixed plantarflexion position of the foot and ankle called equinus. • Hyperextended knee results in anterior shifting of LoG to the knee joint axis. This results in an external extensor moment and puts the posterior joint capsule under tension. • Hyperextended knee results in - a. Lengthening of posterior capsule and cruciate making the joint more unstable. b. Abnormal compression between anterior portion of femoral condyles and tibial plateaus.

Pelvis

1.Excessive Anterior Pelvic Tilt • In a posture in which the pelvis is excessively tilted anteriorly, the lower lumbar vertebrae are forced anteriorly. • The upper lumbar vertebrae move posteriorly to keep the head over the sacrum, thereby increasing the lumbar anterior convexity (lordotic curve). The LoG is therefore at a greater distance from the lumbar joint axes than is optimal and the extension moment in the lumbar spine is increased. • The posterior convexity of the thoracic curve increases and becomes kyphotic to balance the lordotic lumbar curve and maintain the head over the sacrum. • Similarly, the anterior convexity of the cervical curve increases to bring the head back over the sacrum. • Increases in the anterior convexity of the lumbar curve during erect standing increases the compressive forces on the posterior annuli and may adversely affect the nutrition of the posterior portion of the intervertebral disks.

Head

1. Forward Head Posture • A forward head posture is one in which the head is positioned anteriorly and the normal anterior cervical convexity is increased with the apex of the lordotic cervical curve at a considerable distance from the LoG in comparison with optimal posture. • The constant assumption of a forward head posture causes:  Abnormal compression on the posterior zygapophyseal joints and posterior portions of the intervertebral disks  Narrowing of the intervertebral foramina in the lordotic areas of the cervical region. • The cervical extensor muscles may become ischemic because of the constant isometric contraction required to counteract the larger than normal external flexion moment and maintain the head in its forward position. The posterior aspect of the zygapophyseal joint capsules may become adaptively shortened, and the narrowed intervertebral foramen may cause nerve root compression.

POSTURAL ABNORMALITIES ­ ZAS Page 2

1. and • The term lordosis refers to the normal sagittal plane anteriorly convex curves in the cervical and lumbar regions of the vertebral column. The term kyphosis refers to the normal sagittal plane posteriorly convex curves in the thoracic and sacral regions of the vertebral column. • Sometimes an abnormal increase in the normal posterior convexity may occur, and this abnormal condition also may be called a kyphosis. • This condition may develop as a compensation for an increase in the normal lumbar curve, or the kyphosis may develop as a result of poor postural habits or osteoporosis. • Dowager’s hump is an easily recognizable excessively kyphotic condition that is found most often in postmenopausal women who have osteoporosis.  The anterior aspect of the bodies of a series of vertebrae collapse as a result of osteoporotic weakening.  The vertebral body collapse causes an immediate lack of anterior support for a segment of the thoracic vertebral column, which bends forward, causing an increase in the posterior convexity (the hump) and an increase in compression on the anterior aspect of the vertebral bodies. • Diseases such as tuberculosis or ankylosing spondylosis also may cause abnormal increases in the posterior convexity of the thoracic region. • A gibbus or humpback deformity may occur as a result of tuberculosis, which causes vertebral fractures. • Gibbus or humpback deformity is easily recognized by the gibbus (hump), which forms a sharp posterior angulation in the upper thoracic vertebral column.

POSTURAL ABNORMALITIES ­ ZAS Page 3